The recognition and monitoring of localized corrosion at the early stage on the inner wall surface of pipes are extremely difficult and simultaneously the reliable approach for recognition and monitoring is missing. Here we report a spatially resolved method to recognize and monitor the localized corrosion in a non-destructive way based on the permeating hydrogen signal generated from localized corrosion itself. A simulative localized corrosion was created on one side surface of the carbon steel specimen where a dot of wet elemental sulfur was introduced to accelerate the corrosion on the local region. While, the potential on the other side surface (the reverse side of the corrosion site) of the specimen was measured using a scanning Kelvin probe. The results show that the permeating hydrogen generated from localized corrosion easily arrives on the reverse side surface of the corrosion site and then causes a huge change in surface potential. The location resolution of potential distribution can be revealed with micron level. Therefore, it is thought that the location of localized corrosion can be recognized by the permeating hydrogen signal distribution on the reverse side surface of the corrosion site since the region of potential decreasing is highly corresponding to the corrosion site. Moreover, the strength of the permeating hydrogen signal is highly related to the corrosion depth and transient corrosion rate of localized corrosion. This means that the localized corrosion development can also be monitored using the permeating hydrogen signal. Therefore, it can be expected that the localized corrosion occurring on the inner wall surface of pipes or equipment can be recognized and monitored successfully on the outer wall surface in a non-destructive way once the permeating hydrogen is present during the localized corrosion proceeding.

中文翻译：

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通过渗透氢信号以高局部分辨率识别和监测局部腐蚀


在管道内壁表面的早期阶段识别和监测局部腐蚀非常困难，同时缺乏可靠的识别和监测方法。在这里，我们报告了一种空间分辨方法，该方法基于局部腐蚀本身产生的渗透氢信号，以非破坏性方式识别和监测局部腐蚀。在碳钢试样的一侧表面产生模拟局部腐蚀，其中引入了一点湿元素硫以加速局部区域的腐蚀。同时，使用扫描开尔文探针测量样品另一侧表面（腐蚀部位的背面）的电位。结果表明，局部腐蚀产生的渗透氢很容易到达腐蚀部位的背面，然后引起表面电位的巨大变化。电位分布的位置分辨率可以用微米级来显示。因此，由于电位降低区域与腐蚀位点高度对应，因此可以通过腐蚀部位背面的渗透氢信号分布来识别局部腐蚀的位置。此外，渗透氢信号的强度与局部腐蚀的腐蚀深度和瞬态腐蚀速率高度相关。这意味着也可以使用渗透氢信号来监测局部腐蚀的发展。 因此，可以预期，一旦在局部腐蚀过程中存在渗透氢，就可以以非破坏性的方式在外壁表面识别和监测发生在管道或设备内壁表面的局部腐蚀。